Kourtney Kardashian and Justin Bieber went on ANOTHER dinner date last night at The Nice Guy in West Hollywood -- the pair previously went to Universal Studios' Halloween Horror night together and Kourtney went to The Biebs' post-AMAs party last month. And KK was glammed up and sexed up in a criss-cross bra, exposed in her plunge-neck white silk jumpsuit. Girlfriend's look was on fleek!

So just what the hell is the mother-of-three doing hanging out with pop music's #1 bad boy? Who the hell knows! We're guessing Mr. Corey Gamble knows -- he's been on Bieber's team for a minute and obviously he's in a May-December romance with Kardashian-Jenner matriarch, Kris Jenner -- so he's basically on the inside of Hollywood's two biggest moneymaking teams. Not bad for a 35-year-old from the ATL.

Anywho -- what we DO know is that Scott Disick must be super unexcited about his baby mama having dinner with the Biebs. In fact, is this Kourt's way of showing Lord Disick what's up? Kourtney's body is on-point; her connections are 100% A-list and she's going to be just fine without Scott if that's the way things end up. Meanwhile, Scott won't be flipping homes and driving around in a Lambo if he gets booted from the Kardashian family ... live may not be greener on the other side, my Lord!